Move GPU fences into sk_gpu_test

tools/gpu/gl/GLFenceSync.h

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GLFenceSync_DEFINED
+#define GLFenceSync_DEFINED
+
+#include "FenceSync.h"
+#include "gl/GrGLFunctions.h"
+
+namespace sk_gpu_test {
+
+class GLTestContext;
+
+class GLFenceSync : public FenceSync {

[bsalomon, 2016/10/03 17:54:00]

Can the existence of this class be an implementation detail of the GL context
code?

[csmartdalton, 2016/10/03 19:05:40]

Done.

+public:
+    static GLFenceSync* CreateIfSupported(const GLTestContext*);
+
+    PlatformFence SK_WARN_UNUSED_RESULT insertFence() const override;
+    bool waitFence(PlatformFence fence) const override;
+    void deleteFence(PlatformFence fence) const override;
+
+private:
+    GLFenceSync() {}
+
+    static const GrGLenum GL_SYNC_GPU_COMMANDS_COMPLETE  = 0x9117;
+    static const GrGLenum GL_WAIT_FAILED                 = 0x911d;
+    static const GrGLbitfield GL_SYNC_FLUSH_COMMANDS_BIT = 0x00000001;
+
+    typedef struct __GLsync *GLsync;
+
+    typedef GLsync (GR_GL_FUNCTION_TYPE* GLFenceSyncProc) (GrGLenum, GrGLbitfield);
+    typedef GrGLenum (GR_GL_FUNCTION_TYPE* GLClientWaitSyncProc) (GLsync, GrGLbitfield, GrGLuint64);
+    typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GLDeleteSyncProc) (GLsync);
+
+    GLFenceSyncProc        fGLFenceSync;
+    GLClientWaitSyncProc   fGLClientWaitSync;
+    GLDeleteSyncProc       fGLDeleteSync;
+
+    typedef FenceSync INHERITED;
+};
+
+}
+
+#endif